More on the need for a more sophisticated measure of carbon footprints than food miles:
Greener by miles – Sunday Telegraph
Analysis of the industry reveals that for many foods, imported products are responsible for lower carbon dioxide emissions than the same foodstuffs produced in Britain. Even products shipped from the other side of the world emit fewer greenhouse gases than British equivalents.
The reasons are manifold. Sometimes it is because they require less fertiliser; sometimes, as with greenhouse crops, less energy; sometimes, as with much African produce, the farmers use little mechanised equipment. The findings are surprising environmental campaigners, who have, until now, used the distance travelled by food as the measure of how polluting it is.